The long-term goal of our research program is to identify and characterize the mechanism by which extremely low frequency electromagnetic fields (ELF EMF) affect living organisms. As a first step towards this goal we propose to examine the hypothesis that the cell membrane has been altered by interaction with ELF EMF. Using an organism we have previously shown to be effected by ELF EMF, viz. Physarum polycephalum, we propose to investigate the following topics: (a) Transport of Ca ions Ions and Glucose Across the Cell Membrane. Measurements will be made of the influx and efflux of Ca ions ions and the rate of glucose uptake. Experiments have been designed to isolate the membrane-dependent component of transport from the component due to intracellular processes. (b) Electrical Properties of the Cell Membrane. Changes in both membrane surface change and the membrane potential will be measured. (c) Electric and Magnetic Field Components. Electric and magnetic field components will be applied individually and measurements (a) and (b) will be repeated. We have observed that individual field components can produce similar effects in Physarum; these experiments will determine whether or not the effects are similar at the membrane level.